Related Textbooks:

Related Textbooks:

A body cavity without a coelom. Have only one internal space, the digestive cavity. Has a gut cavity, lined with endoderm-derived cells, and surrounded by a mass of tissue derived from the mesoderm. Mesoderm turns to Parenchyma.

Bilateral symmetry

When a plan passes through a sagital plane and there are two equal halfs.

Advertisement

syncytial tegument

non-cilliated body covering that is designed to tegument. Can resist the immune system and digestive juices.

Class Tubellaria

Free-living flatworms.. Are bottome dwellers in marine or freshwater environments. Is dipicted as a paraphyletic taxon.

Class Trematoda

Flukes

Cestoda

Tapeworms

Rhabdites

Are found on the ciliated epidermis and they swell and form a protective mucous shealth around the body when discharged with water.

Dual-glands ( Duogland)

adhesive organs in the epidermis. These organs consist of three cell types viscid and releasing gland cells and anchor cells.

Secretions of Viscid gland cells

fasten microvilli of the anchor cells to the substrate

Secretions of releasing glands

provide a quick, chemical detaching mechanism

planarian mode of nutrition

Are carnivorous , and can detect prey by there chemoreceptors. They entangle prey in mucus secretions from the mucas glands and rhabdites. A planarian grips its prey with its anterior end, wraps its body around the prey item, extends its pharynx and sucks up food in small amounts.

Advertisement

planarian digestive system

bits of food are sucked into the intestine, where phagocytic cells of the gastrodermis complete digestion. Undigested food is egested through the pharynx.

Protonephridia

Primitive osmoregulatory or excretory organ consisting of a tubule terminatining internally with flame bulb or solenocyte.

Flame Cell

Specialized hollow wxxcretory or osmorefulatory structure of one or several small cells containing a tuft of flagella and situated at the end of a minute tubule; connected tubules ultimately open to the outside.

Tube cell

null

subepidermal nerve plexus

The most primitive flateworm nervouse system found in tubellarians. Also have 1-5 pairs of longitudinal nerve cords lying under the muscle layer.

Planarian Sense Organs

Oceli:Is a light sensitive sense organ.

Auricle: earlike lobes on the sides of the head

Tubelarian reproduction

Reproduce asexually (fission) and sexually. All flatworms are monacious

Asexually: Planarians constrict behind the pharynx and seperate into two animals, each of which regenerates the missing parts.

Sexual: Tubellarians develop both male and female organs, which usually open through a common genital pore. After copulation one or more fertilized eggs and some yolk cells become enclosed in a small cocoon.

Tubillarian Locomotion

Are creeping forms that combine musculuar with ciliary movements to achieve locomotion.

intermediate host

1st host of the life cycle.

final host

host in wich sexual reproduction occurs in a life cycle.

Endoparasite

A parasite that resides inside the body of its host organism.

Miracidium

a free-swimming ciliated larva. It penetrates the tissues of a snail and transforms to a sporocyst

Sporocyst

Reproduce asexually wich produce more sporocyst or redia

Redia

Reproduce asexually to produce more redia or cercariae.

Cercariae

Emerge from the snail and can either penetrate the final host directly , penetrate a secon intermediate host, or encyst on aquatic vegetation and develop into metacercariae.

Metacercariae

Juvenile flukes and when eaten into the final host they grow up into adults.

scolex

the holdfast, or so called head, of a tapeworm; bears suckers and in some, hooks, and posterior to it new proglittids are differentiated.

proglottids

portion of a tapeworm containing a set of reproductive organs, usually corresponds to a segment.

strobila

The chain of proglottids of a tapeworm.

Tapeworm nutrition

absorbs its nutrients across its tegument.

Tapeworm reproduction

Each proglottid contains a complete male and female reproductive system, and during mututal cross-fertilization, sperm from each strobila is transferred to the other. The shelled embryos form in the uterus of the proglottid, and they are shed from the worm as it breaks free at zones of muscle weakness between each proglottid.

Taenia saginata

Shelled larvae(oncospheres) are swallowed by cattle wich hatch and they use there hooks to burrow through the intestinal wall into blood and finally reach voluntary muscle, where they encyst and become bladder worms(cysticerci). There the juvenile develops a scolex. When the meat it is living in is undercooked and is eaten by a suitable host the cyst wall disolves, the scolex then attaches to the intestinal mucosa, and new proglotids begin to develop.

Having a body cavity formed from a persisten blastocoal and lined with mesoderm on only one side.

cuticle

A protective noncellular, organic layer,secreted by the external epithelium invertebrates.

Eutely

Condition of a body composed of a constant number of cells or nuclei in all adult members of a species.

Phylum Nematoda

Live in the sea, freshwater, and in soil, from polar regions to the tropics. They parasitize most animals. Feed on bacteria, yeast, fungal hyphae, and algae.

hypodermal cods

where the nuclei are found. Dorsal and ventral cords have longitudinal nerves while the lateral cords have excretory canals.

collagen

a structural protein found in the cuticle. and connective tissue.

body-wall-muscles

they lie beneath the hypodermis and contract longitudinally only. The muscles are arranged in 4 bands seperated by the 4 hypodermal cords. Each muscle cell has a spindle and a noncontractile sarcoplamic portion(cell bodyy). The cell bodys contain nuclei.. For each cells body a muscle arm extends either to the ventral of dorsal nerve.

Nematode locomotion

As muscles on one side of the body contract they compress the cuticle on that side, and the force of the contaction is transmitted( by the fluid in the pseudocoel to the other side of the nematode, stretching the cuticle on that side. this is what produces the thrashing movement seen in neatodes.

Mode of nutrition

when food is sucked into the pharynx when the muscles in its anterior portion contract rapidly and open the lumen. Relaxation of the muscles anterior to the food mass closes the lumen of the pharyns, forcing food posteriorlu toward the intesttine.

amphids

A pair of more complex sensory organs that open on each side of the head at about the same level as the cephalic circle of papillae.

phasmids

Parasitic neatodes bear these near the posterior end and are a sensory organ.

Reproduction

Nematodes are dioecious. Fertrilization is internal, and eggs are usually stored in the uterus until deposition. 4 juvenlie stages are seperated by a mold, shedding, of the cuticle. Many parasitic nematodes have free-living juvenile stages.

Intestinal worm. A femal may lay up to 200,00 eggs a day carried by hosts feces. embryos develop into infective juveniles in 2 weeks. High temp and direct sunlight are lethal.

Ascaris lumbricoides reproduction

Host swallows eggs and the juveniles hatch. They burrow through the intestinal wall into veins and get carried through the heart to the lungs. they break out into alveoli and get carried up to the trachea and reach the pharynx then are swallowed and feed in intestine.

Adults live in the large intestine and cecum. Females migrate to the anal region at night to lay their eggs. When the eggs are swallowed they hatch in the duodenum and warms mature in large intestine.

Large plates in there mouths cut into the intestinal mucosa of the hosts where they suck blood. Eggs pass in the feces and juveniles hatch in the soil. When human skin comes in contact they burrow through skin to blood reach the lungs and intestine.

Cause trichinosis. adults burrow in the mucosa of the small intestine where females produce live young. Juveniles penetrate blood vessels and are carried to any body space. They penetrate muscle cells and then they become the nurse cells.

Females releaselive younginto the bllood and lymphatic system. As they feed mosquitos ingest the young and they develop in the mosquito to the infective stage. They escape from the mescuito when it is feeding on a human and enter through the wound.